Implantable medical device housing having integrated features

ABSTRACT

One aspect is a housing for an implantable medical device, including first housing portion of metal, an intermediate portion of metal and having first and second sides opposite one another and having integrated features, and a second housing portion of metal. The first housing portion is sealed to the first side of the intermediate portion and the second housing portion is sealed to the second side of the intermediate portion thereby forming an housing internal space within first and second housing portions and containing the intermediate portion and its features, such that the features are hermetically sealed within the housing relative to an external space that is outside the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/558,344, entitled “IMPLANTABLE MEDICAL DEVICE HOUSING HAVINGINTEGRATED FEATURES,” having a filing date of Dec. 2, 2014, and which isincorporated herein by reference.

BACKGROUND

There is constant pressure in the marketplace for implantable medicaldevices to be physically smaller in size. Currently, manufacturingmethods for housings of implantable medical devices are machining,stamping, or super plastic forming. Each method has limitations. Withstamping, two housing portions are formed and then joined together toform the complete housing. It is not possible with stamping, however, toproduce housing portions that include separate cavities or featuresintegrated into the housing portion. Stamping also requires uniform wallthickness throughout the part. As such, battery and capacitor assembliesmust be built as separate items and added into the housing portions.

Superplastic forming (SPF) also is a very challenging method ofproducing housing components and also has limitations in producinghousing portions that include separate cavities or features integratedinto the housing portion. The SPF process is very slow, and hassignificantly more variation in dimensions of part features.

For these and other reasons there is a need for the embodiments of thepresent disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of embodiments and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments andtogether with the description serve to explain principles ofembodiments. Other embodiments and many of the intended advantages ofembodiments will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 illustrates a perspective view of an implantable medical devicein accordance with one embodiment.

FIG. 2A illustrates a top perspective view of a housing portion inaccordance with one embodiment.

FIG. 2B illustrates a top perspective view of a housing portionincluding covers in accordance with one embodiment.

FIG. 2C illustrates a cross-sectional view, taken alone line C-C in FIG.2B, of a first housing portion in accordance with one embodiment.

FIG. 2D illustrates a cross-sectional view, taken alone line D-D in FIG.2B, of a first housing portion in accordance with one embodiment.

FIG. 3A illustrates a top perspective view of a housing portion inaccordance with one embodiment.

FIG. 3B illustrates a top perspective view of a housing portionincluding a cover in accordance with one embodiment.

FIG. 4A illustrates an exploded view of a housing for an implantablemedical device in accordance with one embodiment.

FIG. 4B illustrates a sectional view of a housing for an implantablemedical device in accordance with one embodiment.

FIGS. 5A-5D illustrate sectional views of a housing for an implantablemedical device in accordance with various embodiments.

FIG. 6 illustrates a process for manufacturing an implantable medicaldevice in accordance with one embodiment.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. In this regard, directional terminology, such as “top,”“bottom,” “front,” “back,” “leading,” “trailing,” etc., is used withreference to the orientation of the Figure(s) being described. Becausecomponents of embodiments can be positioned in a number of differentorientations, the directional terminology is used for purposes ofillustration and is in no way limiting. It is to be understood thatother embodiments may be utilized and structural or logical changes maybe made without departing from the scope of the present invention. Thefollowing detailed description, therefore, is not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims.

It is to be understood that the features of the various exemplaryembodiments described herein may be combined with each other, unlessspecifically noted otherwise.

In one embodiment, a housing for an implantable medical device includesa first housing portion of metal and having features integrated in thefirst housing portion and a second housing portion also of metal. Thefirst and second housing portions are sealed together thereby formingthe housing with an internal space that is within first and secondhousing portions and that fully contains the features and componentcavity such that they are hermetically sealed relative to an externalspace outside the housing.

By directly integrating features into the first housing, overall spaceis saved in the device, the weight of the device is decreases, therequired assembly steps for the device decrease, stocking requirementsfor separate components is reduced and overall costs are reduced.

In one embodiment, the first and second housing portions each includewalls configured about each respective periphery and are configuredimmediately adjacent each other on the housing at a connection line suchthat the first and second housing portions are readily joined along theconnection line. Accordingly, the housing portions are easy to weldtogether, because the connection line is easily accessed on the outsideof the housing and can be readily welded.

In one embodiment, the features of housing include walls, ribs,component cavities, standoffs, recesses, knuckles, and back-up bands. Inone case, the features comprise ribs extending from the first housingportion, the walls and the ribs together defining a component cavityconfigured to receive components for the medical device. Such featuresprovide numerous advantages, such as allowing for assembly of devicecomponents directly into the housing portion without a separate housing,increased automation of the assembly process of implantable medicaldevice, and the potential of being produced as a single piece flowassembly within a continuous flow assembly line.

In one embodiment, the component cavity substantially contains materialsfor at least one of a capacitor and a battery and is characterized inthat neither the capacitor nor the battery has an independent housingseparate from the first housing portion. In one case, the ribs furtherinclude a step surrounding the component cavity that is configured toreceive a lid, the ribs and step all integrally formed with the firsthousing portion, and the lid sealing the capacitor or the battery. Thecomponent cavity without separate housing avoids duplication ofhousings, thereby allowing for a smaller and lighter overall device. Itavoids forming separate components, thereby reducing componentinventory, reducing exposure to quality-control issues, and loweringoverall product cost.

In one embodiment, the housing includes an intermediate portion betweenthe first and second housing portions, the intermediate portion defininga first chamber between the first housing portion and the intermediateportion and a second chamber between the second housing portion and theintermediate portion. In one case, the first and second housing portionsand intermediate portion each include wall sections configured abouteach respective periphery and configured immediately adjacent each otheron the housing, the wall sections of the first housing portion and theintermediate portion forming a first connection line and the wallsections of the second housing portion and the intermediate portionforming a second connection line. In one embodiment, the portions arereadily joined along the first and second connection lines. Thisconfiguration creates separate chambers that may be useful in separatingcomponents of the medical device, and the materials of the components,so that they can be kept separate. Also, the connection lines allow foreasy access to weld all the portions together.

In one embodiment, the intermediate portion includes a back-up bandadjacent one of the first and second connection lines, the back-up bandconfigured to protect components within the housing when the housing iswelded along the first or second connection lines.

In one embodiment, the first and second housing portions are Ti 6Al-4V(Grade 5 titanium), Ti 6Al-4V ELI (Grade 23 titanium), or Ti 3Al 2.5V(Grade 9 titanium). These materials provide advantages in someapplications, because of their favorable thermal properties.

In one embodiment, a housing for an implantable medical device includesa first housing portion of metal, an intermediate portion of metal andhaving first and second sides opposite one another and having integratedfeatures, and a second housing portion of metal. The first housingportion is sealed to the first side of the intermediate portion and thesecond housing portion is sealed to the second side of the intermediateportion thereby forming an housing internal space within first andsecond housing portions and containing the intermediate portion and itsfeatures, such that the features are hermetically sealed within thehousing relative to an external space that is outside the housing.

By directly integrating features into the first housing, overall spaceis saved in the device, the weight of the device is decreases, therequired assembly steps for the device decrease, stocking requirementsfor separate components is reduced and overall costs are reduced.

In one embodiment, the features include walls, ribs, component cavities,standoffs, recesses, knuckles, or back-up bands. Such features providenumerous advantages, such as allowing for assembly of device componentsdirectly into the housing portion without a separate housing, increasedautomation of the assembly process of implantable medical device, andthe potential of being produced as a single piece flow assembly within acontinuous flow assembly line.

In one embodiment, the intermediate portion defines a first chamberbetween the first housing portion and the intermediate portion and asecond chamber between the second housing portion and the intermediateportion. The separate chambers may be useful in separating components ofthe medical device, and the materials of the components, so that theycan be kept separate.

In one embodiment, the first and second housing portions andintermediate portion each comprise wall sections configured about eachrespective periphery and configured immediately adjacent each other onthe housing, the wall sections of the first housing portion and theintermediate portion forming a first connection line and the wallsections of the second housing portion and the intermediate portionforming a second connection line, wherein the portions are readilyjoined along the first and second connection lines. Accordingly, thehousing portions are easy to weld together, because the connection lineis easily accessed on the outside of the housing and can be readilywelded.

In one embodiment, the intermediate portion includes a back-up bandadjacent one of the first and second connection lines, the back-up bandconfigured to protect components within the housing when the housing iswelded along the first or second connection lines.

In one embodiment, the first and second housing portions andintermediate portion are Ti 6Al-4V (Grade 5 titanium), Ti 6Al-4V ELI(Grade 23 titanium), or Ti 3Al 2.5V (Grade 9 titanium). These materialsprovide advantages in some applications, because of their favorablethermal properties.

In one embodiment, a method of fabricating a housing for an implantablemedical device, includes forming a first housing portion comprisingmetal using an additive manufacturing process such that features areintegrated into the first portion, forming a second housing portioncomprising metal, and joining the first and second housing portionsthereby sealed an internal space of the housing within first and secondportions and fully containing the features such that they arehermetically sealed relative to an external space outside the housing.

By directly integrating features into the first housing, overall spaceis saved in the device, the weight of the device is decreases, therequired assembly steps for the device decrease, stocking requirementsfor separate components is reduced and overall costs are reduced.

In one embodiment, the additive manufacturing process includes at leastone of metal injection molding (MIM), direct metal laser sintering(DMLS), stereolithography (SLA), and three-dimensional printing (3Dprinting). Each of these processes advantageously allow forming of metalportions, which include the advantageous features that are containedwithin the housing, without requiring any further processing of themetal housing portions after the are formed.

In one embodiment, the method includes forming an intermediate portioncomprising metal using an additive manufacturing process such thatfeatures are integrated into the intermediate portion. In one case,joining the first and second housing portions further includes joiningthe intermediate portion between the first and second housing such thatfeatures of the intermediate portion are contained in the interior ofthe housing. The intermediate portion defines separate chambers that maybe useful in separating components of the medical device, and thematerials of the components, so that they can be kept separate.

In one embodiment, forming the first housing portion includes forming acomponent cavity configured for holding materials of at least onecomponent for the medical device. In one case, materials of at least onecomponent for the medical device are assembled into the component cavityand the component cavity is sealed. The at least one component has nohousing other than the component cavity.

By directly integrating features into the first housing, overall spaceis saved in the device, the weight of the device is decreases, therequired assembly steps for the device decrease, stocking requirementsfor separate components is reduced and overall costs are reduced.

FIG. 1 illustrates a perspective view of implantable medical device 10in accordance with one embodiment. Implantable medical device 10includes housing 12 and header 14. Housing 12 includes a first housingportion 16 and a second housing portion 18, which are coupled togetherin a sealed manner along connecting line 20.

In one embodiment, header 14 is mounted onto housing 12 in any of avariety of means. For example, header 14 can be adhered to housing 12using an appropriate implantable grade epoxy bonding material. In oneembodiment, header 14 is a molded elastomeric material, molded plastic,molded urethane, or the like.

Implantable medical device 10 may be any of a variety of therapeuticdevices, including cardiac pacemakers or defibrillators. In suchdevices, housing 12 is configured with electronic circuitry that ishermetically sealed within the interior of housing 12 relative to itsexterior. This electronic circuitry is coupled to bores within header14, which in turn correspond with one or more connectors 22 a/22 b/22 c.Leads (not illustrated), such as cables, can be connected to theimplantable medical device 10 via the header 14, connectors 22 a/22 b/22c and bores. For example, proximal ends of the leads can respectively beinserted into connectors 22 a/22 b/22 c and bores, while the distal endsof the leads can be coupled to electrodes that are surgically secured tobody tissue. Signals can then be sent to and/or received from the bodytissue.

Accordingly, when implantable medical device 10 is implanted within abody, such as within a human body, electronic circuitry hermeticallysealed within housing 12 can be in communication with tissue within thebody where electrodes are placed. Such electronic circuitry can thensense signals at the tissue and/or deliver signals to the tissue throughthe leads coupled within connectors 22 a/22 b/22 c.

In one embodiment, first housing portion 16 and second housing portion18 each metallic and are individually formed and then secured togetherwith a hermetic seal along connecting line 20. For example, the firstand second housing portions 16/18 are a biocompatible metal, such astitanium or platinum, and are welded together, such as via laserwelding, along connecting line 20, to both seal and attach the portions.Alternatively, the first and second housing portions 16/18 can beadhered to each other using an appropriate implantable grade epoxybonding material, for example.

With prior designs, first and second housing portions 16/18 were stampedor superplastic formed. As such, prior designs have relatively smoothwall surfaces without features. First and second housing portions 16/18in accordance with present embodiments, however, are formed usingadditive manufacturing processes, such as metal injection molding (MIM),direct metal laser sintering (DMLS), stereolithography (SLA), orthree-dimensional printing (3D printing). Accordingly, first and secondhousing portions 16/18 in accordance with present embodiments are formedhaving a variety of features that are integrally formed with the firstand second housing portions 16/18. There integral features have numerousadvantages that will be fully discussed below.

FIGS. 2A-2D illustrate views of first housing portion 16 in accordancewith one embodiment. In the figures, first housing portion 16 isillustrated apart from second housing portion 18 such that inner surface17 of first housing portion 16 is visible in the figures. First housingportion 16 includes outer wall 30, first rib portion 32, second ribportion 34, third rib portion 36, and fourth rib portion 38. Each offirst-fourth rib portions 32-38 extend out from inner surface 17 suchthat there are fully contained and hermetically sealed within housing 12when first and second housing portions 16/18 are sealed together.

Outer wall 30 extends out from inner surface 17 about the periphery orperimeter of first housing portion 16. In one embodiment, outer wall 30meets a mirror-image wall on second housing portion 18 at connectingline 20, where the two portions 16/18 are sealed together as discussedabove. First-fourth rib portions 32-38 within outer wall 30 comprisefeatures that are useful for implantable medical device 10.

In one embodiment, first rib portion 32 extends between two locations ofouter wall 30, thereby defining a first component cavity 40. Firstcomponent cavity 40 is bounded by surface 17 on its bottom (as firsthousing portion 16 is oriented in FIG. 2A), and bounded around all sidesby the combination of wall 30 and rib 32. Similarly, second and thirdrib portions 34 and 36 extend between two locations of outer wall 30,thereby defining a second component cavity 42 bounded by surface 17,wall 30 and ribs 34 and 36. In one embodiment, first and second cavities40 and 42 can be specifically configured to contain components ofimplantable medical device 10, such as batteries and capacitors. Forexample, outer wall 30 and first rib portion 32, which form firstcomponent cavity 40, can be configured such that the shape of firstcomponent cavity 40 substantially matches the shape of a battery to beused in implantable medical device 10. Accordingly, a battery may bereadily placed within first component cavity 40 and then easily sealed.Furthermore, as will be discussed more fully below, cavities 40 and 42can be configured to substantially contain the materials that make upcomponents or devices, such as batteries and capacitors, such that thesecomponents or devices can be assembled in place without requiring aseparate housing.

FIG. 2B illustrates a top perspective view of first housing portion 16with first cover 50 in place over first component cavity 40, therebysealing a component, such as a battery, within first component cavity40. In some applications, it is useful if a battery is hermeticallysealed within first component cavity 40. As such, forming first housingportion 16 with outer wall 30 and first rib portion 32 such that thebattery is fully contained within first component cavity 40, allows thebattery to be hermetically sealed within first component cavity 40 bysimply sealing first cover 50 in place over first component cavity 40.

Furthermore, prior designs, where housing portions are stamped or SPFand accordingly do not have features such as ribs 32, required a that acomponent, such as a battery, be a fully contained component with itsown housing that is then attached otherwise fixed within the implantablehousing. With first housing portion 16, however, first component cavity40 is specifically configured such that materials of a battery can beassembled directly into first component cavity 40, without the batteryrequiring its own separate housing.

FIG. 2C illustrates a cross-sectional view, taken alone line C-C in FIG.2B, of first housing portion 16 illustrating first component cavity 40fully containing the materials of a battery in accordance with oneembodiment. In one embodiment, cathode material 46 is placed withinfirst component cavity 40, then a separator material 45 is placed overit, and an anode material 44 is placed over the separator material 45.Once materials 44/45/46 are assembled into place, lid 50 is then weldedin place over them, thereby sealing the materials within first componentcavity 40. In one embodiment, the seal is hermetic. Cathode material 46and anode material 44 can then be electrically coupled to electronicswith implantable medical device 10 such that the combined materials44/45/46 within first component cavity 40 function as a battery forimplantable medical device 10.

In the illustration of FIG. 2C, cathode material 46, separator material45, and an anode material 44 are illustrated as metallic materials, suchas a lithium metal for anode material 44 and iodine, manganese oxide,carbon monofluoride, and silver vanadium oxide for cathode 46. A varietyof other material configurations may also be readily assembled withinfirst component cavity 40. For example, thin film lithium ion batterymaterials having a substrate, electrolyte, current collector, anode,cathode, and a separator can also be assembled within first componentcavity 40.

Also, various other known materials, including liquid forms thereof, arealso readily contained within first component cavity 40. Because firstcomponent cavity 40 is substantially surrounded, on its lower side bysurface 17 and bounded around its entire periphery by the combination ofwall 30 and rib 32, it readily holds and contains any of a variety ofmaterials that can be combined to function as a battery, and keep themisolated from the remaining interior of housing 12. But, instead ofrequiring that these materials be separately packaged in an independentand separate battery housing, first housing portion 16, with itsfeatures such as wall 30, and rib 32, provides an effective housing forthe battery. Accordingly, by foregoing need for a separate batteryhousing, first housing portion 16 saves space in the device 10,decreases weight of the device 10, decreases required assembly andstocking of a separate component and reduces cost.

In one embodiment, outer wall 30 is further configured with step 31 atits upper side and first rib portion 32 is likewise configured with step33 at its upper side. Steps 31 and 33 together substantially surroundthe perimeter of first component cavity 40 such that first cover 50 canbe configured as a simple flat piece of metal with a profile shaped tomatch the profile of first component cavity 40 and fit snuggly overfirst component cavity 40. First cover 50 can be placed onto steps 31and 33 after the battery is assembled in place, and then welded aroundits periphery to hermetically seal the battery within first componentcavity 40.

Because first housing portion 16 is formed via additive manufacturingprocesses, such MIM, DMLS, SLA, or 3D printing, outer wall 30 and firstrib portion 32, including steps 31 and 33, are all integrally formed aspart of forming first housing portion 16. As such, assembly ofimplantable medical device 10 is greatly simplified. After first housingportion 16 is formed, the materials for a battery are assembled intofirst component cavity 40, which was formed as part of the process offorming first housing portion 16. Next, the battery materials are sealedby simply placing first cover 50 along steps 31 and 33, which were alsoformed as part of the process of forming first housing portion 16. Thencover 50 is welded into place thereby hermetically sealing the battery.

When a housing portion is stamped or superplastic formed, any definedareas for placing and sealing components such as materials for a batterymust to added to the housing portion using post-processing techniquesafter the housing portion has been formed. This adds to the cost andtime of the process of assembling a medical device.

Furthermore, integrally forming features, such as first rib portion 32,including steps 31 and 33 into first housing portion 16 allows forincreased automation of the assembly process of implantable medicaldevice 10. For example, first rib portion 32 and outer wall 30 create awell-defined periphery for first component cavity 40 such that anautomated placement device can place readily place the materials of abattery within first component cavity 40 without a human operatorintervening. Similarly, since the combination of steps 31 and 33 createsa ridge the completely surrounds first component cavity 40, an automatedplacement device can also readily place first cover 50 over firstcomponent cavity 40 and within the defined ridge without a humanoperator intervening. This increases the speed of assembly and reducesthe costs.

Furthermore, by integrating first and second component cavities 40 and42 directly into the fabrication of first and/or second housing portions16/18, the entire volume of implantable device 10 is reduced. In priordesigns, independent housings for holding the materials of componentssuch as a battery or capacitor are required. Because these componentsare assembled independently, they have their own housing so that thecomponents can be transferred and stored in preparation for adding themlater to a housing as it is assembled. With such designs, a first wallof the housing portion of the implantable medical device is required,and a second wall is required for an independent housing that isconfigured to hold the battery, capacitor or other component. Becausethe battery and capacitor components in accordance with the presentembodiment are assembled directly into a component cavity defined bycommon walls with the housing portion 16, the overall size ofimplantable device 10 is reduced.

Accordingly, in one embodiment the entire implantable device 10 has thepotential of being produced as a single piece flow assembly within acontinuous flow assembly line. Rather than being formed as separatecomponents, as in prior designs, battery and capacitor subassemblies areformed right into component cavities that are integral in the housingportion 16, thereby reducing component inventory, reducing exposure toquality-control issues, and lowering overall product cost.

Additive manufacturing processes, such MIM, DMLS, SLA, or 3D printing,also affords implantable device designers more design freedom than whatis available with conventional stamping. With additive manufacturing ofhousing portions, features such as threaded embossments, varying wallthicknesses, stepped edges and ribs can all be incorporated into thedesign. This leads to fewer number of components required for thesetypes of products and overall smaller device sizes when compared toconventional stamping methods.

In addition, conventional designs of housings for implantableenclosures, which are produced with stamping or SPF techniques, aretypically limited to using commercially pure titanium (CP Ti)(typically, Grade 1-2 titanium). The mechanical properties of CP Ti makeit conducive for conventional manufacturing methods of stamping or deepdrawing the material to certain geometry. Also, alloys other than CP Tiare seldom specified for implantable enclosures, because it is verychallenging, and in some cases impossible, to produce an enclosure withother titanium alloys in an economical manner.

However, with additive manufacturing processes, such MIM, DMLS, SLA, or3D printing, in accordance with several embodiments, use may be made ofdifferent titanium alloys, such as Ti 6Al-4V (Grade 5 titanium) Ti6Al-4V ELI (Grade 23 titanium) or Ti 3Al 2.5V (Grade 9 titanium).Because Grade 5 and Grade 9 titanium has certain thermal properties andother advantages over Grade 1 or 2 titanium, it would be useful in someapplications to employ a housing with Grades 5, 9, 23 titanium, orother. Using technologies of additive manufacturing, allows more designfreedom for implantable device 10, because these technologies areconducive to producing enclosures with the different titanium alloyslisted. The device designer would have the design freedom to evenspecify CP Ti on certain sections of the device and one of the Ti alloyson another section, depending on the type of manufacturing method beingused to produce the part.

Using additive manufacturing processes to form first and second housingportions 16 and 18, including various features therein, can include avariety of configurations in accordance with various embodiments. Forexample, as illustrated in FIG. 2A, the combination of outer wall 30 andsecond and third rib portions 34 and 36 also define second componentcavity 42. Second component cavity 42 can be used similarly to theabove-described first component cavity 40. For example, second cover 52(illustrated in FIG. 2B) can be welded over second component cavity 42in order to seal in components of implantable medical device 10, such asa capacitor. In one embodiment, outer wall 30 and second and third ribportions 34 and 36, which surround the periphery of second componentcavity 42, are configured with step features such as described abovewith respect to first component cavity 40. In this way, second cover 52fits readily over second component cavity 42 and is readily welded intoplace.

In addition, because second and third rib portions 34 and 36 are spacedapart slightly, the space between them can be used to accommodateconnections between the components within second component cavity 42 andthose outside it. A sealed feedthrough (as will be discussed inadditional detail below) can be located in the space between second andthird rib portions 34 and 36 to fill it in, such the electricalcommunication is provided between the interior and exterior of secondcomponent cavity 42, but also sealing off the opening so thathermeticity is still maintained between the interior and exterior ofsecond component cavity 42.

FIG. 2D illustrates a cross-sectional view, taken alone line D-D in FIG.2B, of first housing portion 16 illustrating second component cavity 42containing the materials of a capacitor in accordance with oneembodiment. In one embodiment, first conductive plate 56 is placedwithin second component cavity 42, then a dielectric material 55 isplaced over it, and a second conductive plate 54 is placed over thedielectric material 55. Once plates 56 and 54 and dielectric 55 areassembled into place, lid 52 is then welded in place over them, therebysealing the materials within second component cavity 42. In oneembodiment, the seal is hermetic. First and second plates 56 and 54 canthen be electrically coupled to electronics with implantable medicaldevice 10 such that the combined materials 54/55/56 within secondcomponent cavity 42 function as a capacitor for implantable medicaldevice 10.

In the illustration of FIG. 2D, first conductive plate 56, dielectricmaterial 55 and second conductive plate 54 are illustrated as asimplified example of a capacitor that can be used in implantablemedical device 10. Various other configurations and materials may bereadily used as well. Because second component cavity 42 issubstantially surrounded, on its lower side by surface 17 and boundedaround its entire periphery by the combination of wall 30 and ribs 34and 36, it readily holds any of a variety of materials that can becombined to function as a capacitor. But, instead of required that thesematerials be separately packaged in a capacitor housing, first housingportion 16, with its features such as wall 30, and ribs 34/36, providesan effective housing for the capacitor. Accordingly, by foregoing needfor a separate capacitor housing, first housing portion 16 saves spacein the device 10, decreases weight of the device 10, decreases requiredassembly and stocking of a separate component and reduces cost.

As also illustrated in FIG. 2A, added manufacturing processes allow forhousing portions 16 and/or 18 to have additional cavities and otherdefined areas with additional features, such as fourth rib portion 38.Furthermore, other configurations and shapes for rib portions, cavities,defined sections and other features of housing portions are possible.

For example, FIGS. 3A and 3B illustrate views of housing portion 66 inaccordance with one embodiment. In the figures, housing portion 66 isillustrated as a single portion apart from a complementary housingportion, such as first and second housing portions 16 and 18 discussedabove and illustrated in FIGS. 2A-2D. Housing portion 66 includesfeatures such as outer wall 70, first rib portion 72, second rib portion74, and third rib portion 76. Each of first-third rib portions 72-76extend from an inner surface of housing portion 66 such that there arefully contained and hermetically sealed within a housing once housingportion 66 is sealed against a complementary housing portion.

As illustrated in FIGS. 3A and 3B, a variety of configurations andshapes are possible for features of housing portion 66. In oneembodiment, first rib portion 72 is an L-shaped portion extending fromouter wall 70 on one end to second rib portion 74 on its other end,thereby defining component cavity 80. As is evident, component cavity 80has a shape on one side that follows the L-shaped portion of first ribportion 72 and a shape on its other side that follows the outline ofwall 70. Accordingly, component cavity 80 can accommodate the assemblyof more components and/or larger components than can first componentcavity 40 described above.

Furthermore, each of outer wall 70 and first rib portion 72 can beconfigured with steps substantially surrounding the periphery ofcomponent cavity 80, such as illustrated and discussed previously withrespect to first component cavity 40. Accordingly, cover 90 can beprovided with a profile to match component cavity 80, as illustrated inFIG. 3B, such that cover 90 is readily placed over component cavity 80within the ridge formed by the stepped portions of outer wall 70 andfirst rib portion 72. Once in place, cover 90 can be welded around itsperimeter in order to hermetically seal component cavity 80 in oneembodiment.

FIGS. 4A-4B illustrate a housing 100 for an implantable medical devicein accordance with one embodiment. Housing 100 includes first housingportion 102, second housing portion 104 and intermediate portion 106. Inone embodiment, intermediate portion 106 is positioned between first andsecond housing portions 102 and 104, such that when first housingportion 102 is sealed to a first intermediate portion 106 on a firstside and second housing portion 104 is sealed to a first intermediateportion 106 on a second side opposite the first, the inside of housing100 is fully hermetically sealed relative to its outside. Furthermore,in one embodiment intermediate portion 106 divides housing 100internally into two separate chambers.

In one embodiment, first housing portion 102 includes main surface 113and wall 112 extending therefrom, second housing portion 104 includesmain surface 115 and wall 114 extending therefrom, and intermediateportion 106 includes main surface 118 and wall 116 extending therefrom.Although FIG. 4A is an exploded view, when housing 100 is fullyassembled and sealed together, wall 112 is sealed to wall 116 along itsupper edge (as oriented in FIG. 4A) and wall 114 is sealed to wall 116along its lower edge (as oriented in FIG. 4A). This defines a firstinner chamber 120 between main surfaces 113 and 118 and a second innerchamber 122 between main surfaces 115 and 118, as illustrated in thecross-sectional view of FIG. 4B.

In one embodiment, first and second chambers 120 and 122 are separatedby intermediate portion 106, and specifically by main surface 118, suchthat chambers 120/122 are hermetically sealed relative to one another.This may be useful in a variety of applications where one of morecomponents, or the materials of one or more components, in one of thechambers 120/122 need to be isolated from components in the otherchamber. For example, in one embodiment electronics can be placed infirst chamber 120, while a battery and/or a capacitor can be assembledin second chamber 122, such that the electronics of the medical device10 are hermetically sealed from the battery and/or a capacitor of thedevice. In addition, various features, such as the ribs and stepsdiscussed above relative to the other embodiments, can be added to anyof the main surfaces 113/115/118 in order to further define componentcavities within chambers 120/122.

Because intermediate portion 106 includes wall 116, which in oneembodiment is substantially parallel with portions of walls 112 and 114,it is readily welded together with first and second housing portions 102and 104 along first and second connecting lines 126 and 128. As such,intermediate portion 106 provides an easily assembled structure thatboth provides a hermetic seal between first and second chambers 120 and122 and also affords ready access to first and second connecting lines126 and 128 thereby insuring the overall housing 100 can be weldedtogether and maintain hermeticity between its interior and its exterior.

In one embodiment, each of first and second housing portions 102 and 104and intermediate portion 106 are formed using additive manufacturingprocesses, such as metal injection molding (MIM), direct metal lasersintering (DMLS), stereolithography (SLA), or three-dimensional printing(3D printing). In another embodiment, intermediate portion 106 is formedusing additive manufacturing processes, while first and second housingportions 102 and 104 are formed using conventional techniques, such asstamping or SPF. Even with first and second housing portions 102 and 104formed with conventional techniques, and accordingly not includingintegrated features, housing 100 can still be provided with featureswhere intermediate portion 106 is formed using additive manufacturingprocesses. Because intermediate portion 106 is formed using additivemanufacturing processes, wall 116 is readily formed to mate with walls112 and 114 of first and second housing portions 102 and 104. Similarly,ribs, such as those illustrated in 2A-3B are readily added to eitherside (or both) of main surface 118 of intermediate portion 106 in orderto create the component cavities, such as described and illustrated inFIGS. 2A-3B.

FIGS. 5A-5D illustrate alternative embodiments of housings150/180/210/240 including various features. FIGS. 5A-5D arecross-sectional illustrations of housings 150/180/210/240, includingfirst housing portions 152/182/212/242, second housing portions154/184/214/244 and intermediate portions 156/186/216/246. Housings150/180/210/240 are similar to housing 100 described above, andaccordingly, in one embodiment, each of first and second housingportions 152/182/212/242 and 154/184/214/244 and intermediate portions156/186/216/246 can be formed using additive manufacturing processes, orintermediate portions 156/186/216/246 can be formed using additivemanufacturing processes, while first and second housing portions152/182/212/242 and 154/184/214/244 are formed using conventionaltechniques.

As with the housing 100 above, housings 150/180/210/240 are eachimplantable medical devices in which intermediate portions156/186/216/246 are positioned between first and second housing portions152/182/212/242 and 154/184/214/244, such that when first housingportions 152/182/212/242 are sealed to intermediate portions156/186/216/246 on a first side and second housing portions154/184/214/244 is sealed to intermediate portions 156/186/216/246 on asecond side opposite the first, the inside of each of housings150/180/210/240 is fully hermetically sealed relative to its outside.Furthermore, in some embodiments, intermediate portions 156/186/216/246divides each of housings 150/180/210/240 internally into two separatechambers. As with housing 100, each of first portions 152/182/212/242include walls 162/192/222/252, each of second portions 154/184/214/244include walls 164/194/224/254 and each of intermediate portions156/186/216/246 include walls 166/196/226/256. Each of walls162/164/166, 192/194/196, 222/226/224, and 252/254/256 are readilywelded to each other to seal housings 150/180/210/240, such that itsinside is sealed relative to its outside.

In addition, each of intermediate portions 156/186/216/246 also includefurther features useful in some applications. For example, intermediateportion 156 in FIG. 5A includes back-up bands 158 positioned adjacentwalls 162, 164, and 166. In order to hermetically seal housing 150,first housing portion 152 is welded to intermediate portion 156 andsecond housing portion 154 is welded to intermediate portion 156.Back-up bands 158 allow added protection within housing 150, especiallyfor electronics and other sensitive components contained within housing150. Because the back-up bands 158 run laterally along walls 162, 164,and 166 inside housing 150, they are between the weld source and thehousing interior and accordingly provide interference or protection toelectronics and other sensitive components within the housing 150 asfirst and second housing portions 152 and 154 are welded to intermediateportion 156 in the area of back-up bands 158. Similar back-up bands 217are illustrated in FIG. 5C. Also, intermediate portions 186 and 246 inFIGS. 5B and 5D have stepped features 189/249 located similarly thatalso function as back-up bands to add some protection for internalelectronics and other sensitive components.

In one embodiment, intermediate portions 156 and 216 in FIGS. 5A and 5Cfurther include features such as standoffs 159/219 and recesses 157/215,which are useful in some applications. During assembly of housings150/210, standoffs 159/219 and recesses 157/215 can be useful inlocating internal components, provide support and further definecomponent cavities. For example, standoffs 159/219 can provide lateralsupport for intermediate portions 156/216 as they contact second housingportions 154/214, thereby supporting intermediate portions 156/216against the housing. Also, standoffs 159/219 can further divide theinside of housings 150/210 into separate sections, such as furthercomponent cavities.

Also, recess 157 of FIG. 5A can be configured to accept a component thatfits uniquely into the recess 157 such that an assembler, or a placementmachine in the case of automated assembly, can readily place thecomponent in the correct location within housing 150. Also, recess 215of FIG. 5C can be located uniquely to allow standoff 219 to beaccurately placed by having it fit into recess 215. This will alsofacilitate ease in assembly and help avoid mistakes in aligning partsduring assembly. Furthermore, intermediate portion 186 in FIG. 5Bincludes features such as recess 188 and knuckle 187, each of which alsoare helpful in assembling housing 180 and ensuring accurate placement ofcomponents within the housing 180.

In one embodiment, one or more of the housing portions and intermediateportions include features such as feedthroughs 230/248/250 asillustrated in FIGS. 5C and 5D. For example, feedthrough 230 is locatedin first housing portion 212, and provides conductive access between theinside of housing 210 and its outside while still maintaininghermeticity therebetween. In one embodiment, feedthrough 230 includes aninsulative portion 232 and conductors 234 passing through insulativeportion 232. Insulative portion 232 is nonconductive and maintains ahermitic seal relative to the adjacent housing portion 212. Conductors234 are electrically conductive and pass through the insulative portion232 and also maintain a hermitic seal relative to the adjacentinsulative portion 232. Conductors 234 allow electrical connectivitybetween components within housing 210 to those outside housing 210 whilemaintaining hermeticity therebetween.

Feedthroughs 248 and 250 are similarly configured and illustrated inFIG. 5D. Feedthrough 248 is located in second housing portion 244, andprovides conductive access between the inside of housing 240 and itsoutside while still maintaining hermeticity therebetween. Feedthrough250 is located in intermediate portion 246, and provides conductiveaccess between two internal chambers of housing 240 on either side ofintermediate portion 246, while still maintaining hermeticitytherebetween.

In each case, feedthroughs 230/248/250 are features formed as part offorming the respective portions in which they reside, first housingportion 212, second housing portion 244, and intermediate portion 246.With the additive manufacturing processes used for forming the variousportions, these features are readily integrated into the portions.

In fact, because the above-described housing portions and intermediateportions, including the various above-described features, such asback-up bands, recesses, standoffs, feedthroughs, etc. are formed withadditive manufacturing, such MIM, DMLS, SLA, or 3D printing, each ofthese above-describes features are integrally formed as part of formingthe housing portions or the intermediate portions. This leads to fewernumber of components required for these types of products and easier andfaster assembly of the portions to form the overall product, loweringerrors and reducing cost.

FIG. 6 illustrates a process 300 for manufacturing an implantablemedical device, such as described above with respect to FIGS. 1-5D. Inone embodiment, a first housing portion is manufactured at step 310. Insome embodiments, a first housing portion, such as first housingportions 16/102/152/182/212/242, is formed using additive manufacturing,such MIM, DMLS, SLA, or 3D printing. In such cases, forming of the firsthousing portion includes integrally forming features included in thehousing portion, such as walls, ribs, component cavities, standoffs,back-up bands and so forth.

For example, in the case of MIM, such features are built into the moldparts before the metal is injecting in, such that the features areintegrally molded into the housing portion. In the case of 3D printing,the printing is controlled such that the features are printed with thehousing portion such that the features are integrally formed with thehousing portion. In some embodiments, forming the first housing portionincludes forming at least one component cavity, such as first componentcavity 40 illustrated in FIGS. 2A and 2C integrally into first housingportion.

In some embodiments, such as where an intermediate portion with featuresis used, such as illustrated in FIG. 4A, the first housing portion canalso be formed by conventional means, such as stamping or SPF.

In one embodiment, a second housing portion is manufactured at step 312.In some embodiments, a second housing portion, such as second housingportions 18/104/154/184/214/244, is formed using additive manufacturing,such MIM, DMLS, SLA, or 3D printing. In such cases, forming of thesecond housing portion includes integrally forming features included inthe housing portion, such as walls, ribs, component cavities, standoffs,back-up bands and so forth, just as described above for the firsthousing portion. In other embodiments, such as where an intermediateportion with features is used, such as illustrated in FIG. 4A, thesecond housing portion can also be formed by conventional means, such asstamping or SPF.

In some embodiments, an intermediate portion is manufactured at step314. In some embodiments, such as illustrated in FIG. 1, an intermediateportion is not used, and in such case step 314 is optional. When theintermediate portion is used, the intermediate portion, such asintermediate portions 106/156/186/216/246, is formed using additivemanufacturing, such MIM, DMLS, SLA, or 3D printing. In such cases,forming of the intermediate portion includes integrally forming featuresas part of the intermediate portion.

At step 316, the housing portions are assembled to form an implantabledevice, such as implantable medical device 10. Where only first andsecond housing portions have been formed, various components are firstplaced on first and/or second housing portions. Where an intermediateportion is formed, various components may also be place on theintermediate portion as will. In either case, features, such as ribs,walls, component cavities, standoffs, recesses, knuckles, back-up bands,etc., which are integrated into first and second housing portions andinto the intermediate portion are used to facilitate placement of thevarious components that will ultimately be sealed within the housing.Components such as electronic circuit boards, batteries and capacitorscan fit into cavities and other recesses that are formed by the featuresthat are integrated into the first and second housing portions and theintermediate portion. In some cases, lids may then seal some of thesecomponents, such as batteries and capacitors as previously discussed,into one of the housing portions. The assembly of the components can beby hand or with automation and placement is aided by the featurespresent in the housing portions.

Next, at step 318, the housing portions are brought together, such asillustrated in FIG. 1, and then the housing portions are sealed togetherto form the housing and hermetically seal the components within thehousing. In one embodiment, in order to hermetically seal the housing, alaser weld is used along the interface between the first and secondhousing portions, such as along connecting line 20 in FIG. 1.

Where a first and second housing portion and an intermediate portion areformed, all three portions are connected, such as illustrated in FIGS.4A and 4B. For example, first housing portion 102 is welded tointermediate portion 106 along second connecting line 128 and secondhousing portion 104 is welded to an opposite side of intermediateportion 106 along first connecting line 126 (as illustrated in FIG. 4B).Similarly, sealing the portions this way hermetically seals thecomponents within the housing relative to its exterior.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

What is claimed is:
 1. A housing for an implantable medical devicecomprising: a first housing portion comprising metal; an intermediateportion comprising metal and having first and second sides opposite oneanother and having integrated features; and a second housing portioncomprising metal; wherein the first housing portion is sealed to thefirst side of the intermediate portion and the second housing portion issealed to the second side of the intermediate portion thereby forming anhousing internal space within first and second housing portions andcontaining the intermediate portion and its features, such that thefeatures are hermetically sealed within the housing relative to anexternal space that is outside the housing.
 2. The housing of claim 1,wherein the features comprise at least one of a group comprising walls,ribs, component cavities, standoffs, recesses, knuckles, and back-upbands.
 3. The housing of claim 1, wherein the intermediate portiondefines a first chamber between the first housing portion and theintermediate portion and a second chamber between the second housingportion and the intermediate portion.
 4. The housing of claim 3, whereinthe first and second chambers are hermetically sealed from each other bythe intermediate portion.
 5. The housing of claim 1, wherein the firsthousing portion and the second housing portion are each characterized bythe absence of features, such that they can be formed from stamping. 6.The housing of claim 1, wherein the first and second housing portionsand intermediate portion each comprise wall sections configured abouteach respective periphery and configured immediately adjacent each otheron the housing, the wall sections of the first housing portion and theintermediate portion forming a first connection line and the wallsections of the second housing portion and the intermediate portionforming a second connection line, wherein the portions are readilyjoined along the first and second connection lines.
 7. The housing ofclaim 6, wherein the intermediate portion comprises a back-up bandadjacent one of the first and second connection lines, the back-up bandconfigured to protect components within the housing when the housing iswelded along the first or second connection lines.
 8. The housing ofclaim 6, wherein at least one of the intermediate portion and first andsecond housing portions comprise a feature configured to accept acomponent that fits uniquely into the feature, such that an assembler orplacement machine, can place the component in the correct locationwithin the housing.
 9. The housing of claim 1, wherein the first andsecond housing portions and intermediate portion comprise one of Ti6Al-4V (Grade 5 titanium), Ti 6Al-4V ELI (Grade 23 titanium), and Ti 3Al2.5V (Grade 9 titanium).
 10. A housing for an implantable medical devicecomprising: a first housing portion comprising metal and having featuresintegrated in the first housing portion; a second housing portioncomprising metal; and an intermediate portion between the first andsecond housing portions, the intermediate portion defining a firstchamber between the first housing portion and the intermediate portionand a second chamber between the second housing portion and theintermediate portion; wherein the first and second housing portions areeach sealed to the intermediate portion such that each of the first andsecond chambers are hermetically sealed relative to an external spaceoutside the housing and such that the features are sealed within thefirst chamber.
 11. The housing of claim 10, wherein the first and secondhousing portions and intermediate portion each comprise wall sectionsconfigured about each respective periphery and configured immediatelyadjacent each other on the housing, the wall sections of the firsthousing portion and the intermediate portion forming a first connectionline and the wall sections of the second housing portion and theintermediate portion forming a second connection line, wherein theportions are readily joined along the first and second connection lines.12. The housing of claim 10, wherein the intermediate portion comprisesa back-up band adjacent one of the first and second connection lines,the back-up band configured to protect components within the housingwhen the housing is welded along the first or second connection lines.13. The housing of claim 10, wherein the integrated features comprise atleast one of a group comprising walls, ribs, component cavities,standoffs, recesses, knuckles, and back-up bands.
 14. The housing ofclaim 10, wherein the first chamber and the second chamber arehermetically sealed relative to each other by the intermediate portion.15. The housing of claim 10, wherein the first and second housingportions comprise one of Ti 6Al-4V (Grade 5 titanium), Ti 6Al-4V ELI(Grade 23 titanium), and Ti 3Al 2.5V (Grade 9 titanium).